Dispenser devices of the two-dose type are well known. They are applicable particularly in dispensing medication and in particular vaccines into the nose. In existing devices, in order to subdivide the dose into two half-doses, e.g. so as to dispense them separately into respective ones of the two nostrils, two elements are generally provided, one supporting a reservoir, and the other supporting the piston. When they are compressed axially towards each other, the first half-dose is delivered through the dispensing orifice into the nostril. In order to subdivide the dose, the piston is stopped half way along its stroke by a shoulder, and, in order to cause it to travel over the second half of its stroke, i.e. in order to dispense the second half-dose, it is necessary to turn the piston element manually relative to the reservoir. That type of system is safe and accurate, but it requires relatively complex manipulation and therefore both hands to be used to obtain the desired result, and to make it possible to dispense the two half-doses successively into respective ones of the two nostrils. Unfortunately, the use of two hands for dispensing the two half-doses successively into respective ones of the two nostrils may be undesirable in certain cases, and in particular, it can be necessary to have one hand free for holding the head of a child to whom the fluid is being administered, for example.
In order to guarantee that each half-dose is dispensed in full, and in particular, in order to avoid partial dispensing and in order to achieve finely-sprayed dispensing, it is possible to provide energy accumulation means, such means generally having breakable bridges of material. Unfortunately, such a type of energy accumulation means, which is known from the state of the art, is unreliable because the bridges of material can break while the device is in transit, i.e. before it is used. Similarly, they do not make it possible to guarantee reliable and constant energy accumulation, it being possible for the breaking thresholds of said breakable bridges to vary due to various parameters, and in particular due to manufacturing tolerances. In addition, it is difficult to predetermine the force required to break said bridges of material, and thus the actuating force necessary for actuating the device.